Setting units, in particular in the form of crowns fitted such that they can be rotated and/or pulled out, allow the setting of various movable component parts, which are located within the associated timepiece, for example, a date display, a world time disc, a moon disc, an inner bezel, which is common in particular with diving watches and which is used there to display the remaining diving time, or the like. Here, the setting is normally performed manually by the user of the timepiece, once the user has brought the setting unit into a corresponding position, which allows the setting, whereas the setting possibility is otherwise deactivated by disengagement. In the case of diving watches or other applications in which safety-relevant aspects play a role, automatically switching setting units, which can automatically perform the disengagement and engagement, are also known, for example from document EP 1 557 728.
The movable component part, preferably an inner bezel in the case of document EP 1 557 728, is secured here in the set position via a catch spring, which engages with corresponding notches, normally formed equidistantly on the movable component part. In addition, an indexing during the setting of the component part is achieved by the cooperation between catch spring and notches in so far as the user of the setting unit perceives the individual processes of engagement of the catch spring with each of the notches as individual steps of the setting process.
According to document WO2002/044818, the holding of the movable component part in the set position and also the indexing of the setting process can also be implemented via spring-loaded pins or leaf springs, which can engage with corresponding notches.
Another example of a setting unit is disclosed in document FR 1 602 849. The device described there allows the setting of an inner bezel, which is held in the set position by means of a corrugated leaf spring, which presses onto the inner bezel and produces a frictional force.
A setting unit, in this case a crown, is also proposed in document US2002/0167866 and allows the setting of an inner bezel. This is held in the set position by a part made of rubber-like material, which is provided between the bezel and the timepiece casing, that is to say by means of frictional force.
In the case of the previously known setting units, the holding of the movable component part in the set position and, where provided, the indexing of the setting process is/are therefore implemented via catch springs or pins cooperating with notches or via friction effects.
This is not always desirable, or even entails disadvantages for various reasons. For example, the spring force of the catch spring or the frictional force may not always be set with the necessary accuracy, for example due to manufacturing fluctuations or the structural design of the catch spring. In particular, the spring force of leaf springs allows less accurate setting than that of balance-springs. A catch spring furthermore causes an independent, additional engagement point at the periphery of the movable, settable component part, which may entail an increased spatial requirement and also, depending on the type of movable component and the parts otherwise still cooperating therewith, an increased complexity or limitation in terms of the design of the associated timepiece. Corresponding notches also have to be provided on the movable component part, which may be undesirable. In addition, only a very rough securing of the component part in the set position can be achieved by frictional forces alone, but no indexing of the setting process.